250 Proceedings of Indiana Academy of Science. 
area. Subterranean piracy is dependent upon differential work of the 
surface streams in their downward cutting. Those stream basins or portions 
of stream basins which are relatively high above neighboring stream basins 
in limestone regions are subject to diversion by subterranean piracy. The 
most notable case yet described is that described by Beede in his paper 
on the “Cycle of Subterranean Drainage, as Illustrated in the Bloomington, 
Indiana, Quadrangle,” published in the Proceedings of the Indiana Acad- 
emy of Science, 1910. In this case several square miles of the upper por- 
OUTLINE MAP OF 
MONROE AND LAWRENCE 
COUNTIES INDIANA 
SHOWING LOCATION 0, 
DETAIL MAP OF THE 
CUT-OFF PLAWATION 
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| Est 
204 
9 
2 
2u4 
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a 
2W4 2AN 
ie: 
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tion of Indian Creek drainage basin have been diverted by subterranean 
piracy into the more deeply intrenched streams on either side of the head- 
waters of Indian Creek. 
The third type of stream piracy is the type with which the present 
paper deals. It is commonly found where a larger stream has reached the 
stage of maturity in an area of considerable relief. By the lateral planation 
of the mature main stream a nearly parallel minor stream may be literally 
cut into two streams, each entering the master stream independently. The 
upper part of the once continuous stream will enter the main stream at the 
place where the master stream invaded the valley of the minor stream. 
The lower part of the minor stream will be left in a valley far too large 
